How Big Is a Pearl? See Pearl Sizes at True Size
A pearl’s size is its diameter in millimeters.1 Choose a size below to see a pearl drawn at that size, next to the outline of a US quarter, which is 24.26 mm across, and to see which pearl types typically come in it.2
The pearl you chose, next to the outline of a US quarter, 24.26 mm across.
Set the scale to life size
Hold a ruler to the screen and move the slider until the bar measures 50 mm, or until a US quarter laid on the circle just covers it. The setting is saved on this device.
- 2 mm
- 4 mm
- 6 mm
- 8 mm
- 10 mm
- 12 mm
- 14 mm
- 16 mm
- 18 mm
- 20 mm
| Pearl type | Typical size | Size range |
|---|---|---|
| Akoya cultured pearl | 6–8 mm3 4 5 6 7 | 2–11 mm3 4 5 6 7 |
| Freshwater cultured pearl | 3–15 mm6 7 | 3–25 mm6 7 |
| Keshi cultured pearl | Not recorded | under 1 mm to 16 mm (larger ones are very rare)6 8 |
| South Sea cultured pearl | 9–16 mm5 6 7 | 8–18 mm5 6 7 |
| Tahitian cultured pearl | 8–14 mm5 6 7 9 | 8–20 mm5 6 7 9 |
Seeing true size on your screen#
Screens differ in how large they draw a millimeter, so the drawings may be larger or smaller than life until you set the scale. Open “Set the scale to life size” and move the slider until the bar measures 50 mm on a ruler, or until a US quarter laid on the circle just covers it. With JavaScript off you can still check: measure the 20 mm pearl with a ruler, and every drawing is off from life size by the same proportion.
How pearls are measured#
CIBJO’s standards give a pearl’s measurements in millimeters, rounded down rather than up. A round pearl is measured across its widest diameter and, once drilled, across the widest diameter at right angles to the drill hole.1 The page pearl size guide explains how strands are measured and how to choose a size.
Where the sizes come from#
The typical sizes and size ranges come from the Learn About Pearls dataset, and the numbers in the table point to each figure’s own sources. GIA cautions that pearls of every type can occur outside their typical ranges.7
References#
- CIBJO, The World Jewellery Confederation, Pearl Commission (2026). The CIBJO Pearl Book (Pearl Blue Book) 2026. Source · Archived copy (accessed 2026-10-25)
- United States Mint. Coin Specifications. Source · Archived copy (accessed 2026-10-26)
- Areeya Manustrong (2018). Very Small Akoya Cultured Pearls. Source · Archived copy (accessed 2026-10-25)
- Artitaya Homkrajae (2024). Remarkably Large Akoya Bead Cultured Pearls. Source · Archived copy (accessed 2026-10-25)
- Fisheries Agency of Japan (水産庁) (2026). 真珠養殖をめぐる情勢について (On the situation of pearl culture). Source · Archived copy (accessed 2026-10-25)
- CIBJO Pearl Commission (2025). CIBJO Guides Describing and Classifying Natural and Cultured Pearls, the Producing Molluscs & Responsible Pearling. Source · Archived copy (accessed 2026-10-25)
- Gemological Institute of America (GIA), FAQ. What are the main types of cultured pearls and what are their distinctive characteristics?. Source · Archived copy (accessed 2026-10-25)
- H. A. Hänni (2006). A short review of the use of "keshi" as a term to describe pearls. Source · DOI 10.15506/JoG.2006.30.1.51 · Archived copy (accessed 2026-10-25)
- Oïhana Latchere and others (2018). Influence of water temperature and food on the last stages of cultured pearl mineralization from the black-lip pearl oyster Pinctada margaritifera. Source · DOI 10.1371/journal.pone.0193863 · Archived copy (accessed 2026-10-25)
- Written by
- Learn About Pearls editors
- Fact-checked
- Learn About Pearls editors,
- Reviewed by
- Simon,
- First published
- Publisher
- Unique Pearl, a pearl jeweler
Revision history
- : First published. First published
How to cite this page
- APA
- Learn About Pearls editors. (2026). How Big Is a Pearl? See Pearl Sizes at True Size. Learn About Pearls. https://learnaboutpearls.com/tools/pearl-size-visualizer/
- MLA
- “How Big Is a Pearl? See Pearl Sizes at True Size.” Learn About Pearls, Unique Pearl, November 4, 2026, learnaboutpearls.com/tools/pearl-size-visualizer/.
- Chicago
- Learn About Pearls editors. “How Big Is a Pearl? See Pearl Sizes at True Size.” Learn About Pearls. Unique Pearl. Last modified November 4, 2026. https://learnaboutpearls.com/tools/pearl-size-visualizer/.
- BibTeX
@misc{lap-tools-pearl-size-visualizer, title = {How Big Is a Pearl? See Pearl Sizes at True Size}, author = {{Learn About Pearls editors}}, year = {2026}, howpublished = {\url{https://learnaboutpearls.com/tools/pearl-size-visualizer/}}, note = {Learn About Pearls, published by Unique Pearl}}
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